Glass cloth in metal forging

ABSTRACT

In forging a metal piece which has been heated to a temperature above that of the forging dies, the metal piece is insulated from the dies by glass cloth.

United States Patent [19] Gurganus et al.

[ GLASS CLOTH 1N METAL FORGING [75] Inventors: Thomas B. Gurganus, AvonLeland L. Grubb, Parma, both of Ohio [73] Assignee: Aluminum Company ofAmerica, Pittsburgh, Pa.

[22] Filed: May' 25, 1973 [21] Appl. No.1 363,930

[52] U.S. Cl. 29/423 51 Int. Cl B23p 17/00 [58] Field of Search29/423,424; 72/41, 42, 72/46 [56] References Cited 1 UNITED STATESPATENTS 2,706,850 4/1955 Sejournet et a1 29/423 1 Feb. 4, 1975 3,021,5942/1962 Clatot et al. 29/424 3,181,324 5/1965 Labino 72/42 3,690,1359/1972 Gagin et al. 72/42 OTHER PUBLICATIONS Forging of Titanium Alloys,Vol. 5, Metals Handbook, Forging and Casting, 8th Edition, 1970, pp.142-147.

Primary Examiner-Richard J. Herbst Assistant Examiner-E. M. CombsAttorney, Agent, or FirmDaniel A. Sullivan, Jr.

[57] ABSTRACT In forging a metal piece which has been heated to atemperature above that of the forging dies, the metal piece is insulatedfrom the dies by glass cloth.

16 Claims, 5 Drawing Figures PATENTEUFEB 5.863.325

. SHEET 1 [1F 3 Huh A MIHH FIG. I

PI'HENTED 3.863.325

sum 20F 3 FIG. 2

IIIIIII'III lllilllllll III as:

llllmm. .nmmlliillll FIG. 3

GLASS CLOTH IN METAL FORGING BACKGROUND OF THE INVENTION The presentinvention relates to the forging of metal and, more particularly, to theforging of titanium.

Background material is provided in the article Forging of TitaniumAlloys at pages 142 to 148 in Vol. 5 of the METALS HANDBOOK, FORGING ANDCASTING, American Society for Metals, 8th edition, 1970, and thisarticle is incorporated here by reference.

As used herein, the term titanium refers to any metal containing atleast 30 percent by weight of the element titanium.

Titanium forging must be typically carried out at high enoughtemperature to give the titanium metal piece to be forged sufficientductility to allow metal flow into the forging die cavities atreasonable times and pressures and to prevent the possibility ofcracking of the titanium piece. The forging dies for forging titaniumare generally heated to an elevated temperature to prevent their actingas heat sinks, robbing heat from the titanium to be forged. If thetitanium metal were to suffer significant temperature depression whereit contacts the dies, less, or no, metal flow will occur in the titaniummetal at these points of lower temperature. It is generally noteconomically practical, however, to heat the dies to as high atemperature as the temperature of the titanium piece. Consequently, theforging of titanium alloys still has associated with it, in general, asubstantial temperature difference between the piece of titanium alloybeing forged and the forging dies. Therefore, before the presentinvention, it was the normal practice to carry out the forging oftitanium alloys by insulating the hotter piece of titanium alloy to beforged from the forging dies using asbestos roll board, which is apliable asbestos-based sheet material. It had been the practice to applythis material usually in a sheet thickness of 1/16 inch, with a doublethickness being used for some applications. Furthermore, in the practicewithasbestos, it has been customary to use additional thicknesses ofasbestos insulation at those portions of a metal piece to be forgedwhere larger amounts of metal flow are desired. This use of extrathicknesses of asbestos is termed shimming or slulgging." This shimminghas the effect of achieving selective metal flow at a particularlocation by exerting pressure first at the portions where metal flow isto be higher. The extra shimming insulation also keeps the metaltemperature high and allows the metal to flow more readily.

Asbestos has, however, the disadvantage that it may be harmful to themen carrying out the process. In addition, it has given a pockmarked orpitted surface which is difficult to clean and which often must bemachined away beforeultrasonic testing can be carried out.

SUMMARY OF THE INVENTION In view of the above, it is an object of thepresent invention to provide a substitute for asbestos sheet insulationin forging operations requiring'the insulation of the metal piece beingforged from the forging dies.

More particularly, it is an object of the present invention to providean insulating material, novel in the forging of titanium alloys, forreducing heat transfer between a piece of titanium alloy to be forgedand the dies used for forging.

Another object of the present invention is to provide a titanium metalproduct having an improved surface both as regards appearance and asregards amenability to ultrasonic inspection.

These as well as other objects, which will become apparent in thediscussion that follows, are achieved, according to the presentinvention, by a method of forging a metal piece between dies, includingthe steps of heating the metal piece to a temperature above that of thedies, insulating the higher temperature metal piece from the dies withglass cloth, and squeezing the insulated metal piece between the diesfor causing metal flow for forging.

By the term die," we mean both flat dies, i.e., platens, and dies havingcontoured surfaces.

BRIEF DESCRIPTION OFTHE DRAWINGS FIG. 1 is an isometric, exploded viewillustrating the method of the present invention.

FIG. 2 is an isometric view of a forging made according to the presentinvention.

FIG. 3 is an isometric view of an alternate embodiment of the presentinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A. FIG. I

Referring now to FIG. 1, there is illustrated an example of a forgingprocess according to the present invention. The different pieces used inthe process are shown in exploded view. From the bottom there is shown adie 10 with a cavity 11, which roughly has an outline, in thehorizontal, of a rectangle. Within cavity 11 is a protrusion 12, whichis surrounded by a gutter 13. Above die 10 is a glass cloth 14, then atitanium piece 15 which is to be forged to a desired shape, on top ofpiece 15 a second glass cloth 16, and, finally, the top die 17. The topdie has a flat-faced punch section (not shown) 1 which fits into cavity11 so that pressure may be transferred from appropriate forgingequipment (not shown) onto the titanium piece 15 for forging it. The

titanium metal piece 15 is hotter than the dies and is insulated againstheat loss by the two glass cloths. During forging, the titanium metal issqueezed between the top die. 17 and the bottom die 10 and caused toflow under forging pressures into gutter 13 to form the desired shape,which is illustrated in FIG. 2 and which consists of a peripheral rib l8protruding from one side of a web 19.

B. Outline of the Preferred Process In carrying out the process of theinvention, a preferred and usual practice is as follows.

As is well known in the art of forging titanium, steps must be taken toprevent the buildup of significant thickness of alpha-case on a titaniumworkpiece while it is being heated in a furnace to forging temperature.Diffusion of oxygen into the piece would, for instance, serve tostabilize alpha-phase at the surface. We prefer to spray a glass fritcontained in trichloroethane vehicle onto the titanium piece to beforged, before putting it into the preheat furnace, where the piece isheated to an appropriate forging temperature. The glass frit, for

instance a soda barium glass or a borosilicate glass, melts and formsa'protective coating to bar oxygen from reaching the titanium surfacewhere it would act to form a significant alpha-case thickness. It isalso possible to exclude oxygen using a vacuum or inert atmospheres.

In conjunction with the preheating of the titanium, the top and bottomdies are heated in a furnace to some die temperature desired forforging. The dies are then removed from the furnace on a mobile car andlifted by a crane for transport to the forging press-where they aremounted securely to the press bed and ram, respectively.

Following the mounting of the die members to the press, both the upperand lower dies may be sprayed with a lubricating mixture. v

The lower glass cloth may be initially sprayed with a lubricatingmixture to give it some weight to allow it to be easily laid down intothe cavity of the lower die. The glass cloth usually extends out intothe area of the die adjacent to the die cavity, perhaps a distance of 2inches. The lower glass cloth may be sprayed with additional lubricatingmixture after it has been laid into the cavity.

The titanium piece, which has been preheated to an appropriatetemperature above the temperature of the dies, is removed from itsheating furnace and laid into the cavity of the lower die, where itrests on the lower glass cloth. v

The upper glass cloth, which may also have been given a preliminaryspraying with a lubricant mixture, is then laid on' top of the titaniumpiece and extends outwards on each side of the slab a distance, forexample, of 2 inches.

The pre-spraying of the glass cloths with a lubricant mixture has beenfound to be advantageous in that it promotes the settling of the lowerglass cloth into all of the topography of a die cavity. The pre-sprayingalso prevents fume-exhaust suction air currents and cooling-fan aircurrents atthe work location from causing the upper or lower glasscloths to blow out of place on a die cavity.

allowed to cool, and transported to a cleanup area. In-

the cleanup, various undesired substances are removed from the titaniumforging. For example, a scale usually remains as a result of the heatingof the forging. Also, remnants of the glass cloth, lubricant residue,and glass coating must be removed. Cleaning may be done by mechanicalmeans such as grit or shot blasting of the forging or by chemical meanssuch as dipping the forging into a hot salt bath, for example, as in oneof the Kolene processes available from the Kolene Corporation ofDetroit, Michigan.

Following cleaning, the titanium forging is dipped in a hot picklingbath of a combination of nitric and hyv drofluoric acids to remove anyalpha-case. The forging may then be inspected and repaired if necessaryfor further forging operations or for supply as a finished product tothe customer.

After carrying out a forging operation, the dies are sprayed withcompressed air and/or steam to clean the die cavities for the nextcycle.

Focussing on a particular titanium forging to be made, it will typicallybe forged in stages using a number of die sets perform dies, first,second and third' blocker dies, and finish dies, for example.

C. The Process Parameters forge a piece of titanium alloy depends uponthe particular alloy type. There are three basic titanium alloy types,these being (1) the alpha alloys, (2) the alphabeta alloys, and (3) thebeta alloys, depending upon which is the main phase, or phases,generally stable at room temperature. On this basis, pure titanium isclassed as an alpha alloy herein. The temperature of the metal piece'tobe forged, when it is an alpha alloy, is generally in the range l,500 to2,000F. Preferably, the temperature of an alpha alloy metal piece iskept below that temperature at which grain coarsening begms.

In the case of'metal pieces made of alpha-beta alloys, the temperatureof the piece is generally in the range of l,400 to l,800F for forging.It may be advantageous to forge a piece of alpha-beta alloy above thebeta transus, for example at a temperature in the range from the betatransus to 300F above the beta transus, for increasing forgeability orfor certain property level improvement such. as improved notchtoughness, as compared with what would be obtained when forging belowthe beta transus. See the above-referenced Forging of Titanium Alloys. 7

For beta alloys, the metal piece to be forged is generally brought tothe range l,325 to l,850F.

Die temperature is determined by the balancing of a number of differentfactors. Die material selection factors are described in general in thesections entitled Die Steels and Factors in the Selection of DieMaterial appearing at pages 27 to 30 in the Metals Handbook volumereferred to above in the BACKGROUND OF THE INVENTION; these sections areincorporated here by reference. In theory, it should be desired to use adie temperature equal to the temperature of the metal piece to beforged. However, in the case of forging titanium, die material that canserve at a temperature equal to that of the metal piece is usuallyeconomically not feasible. Thus, it is often necessary to use a diematerial which can only be heated to a temperature still significantlylower than the temperature of the metal piece. For example; an AlSlClass T2 die steel, for example FX2 steel of A. Pink] and Sons Co.,Chicago, lllinois or I-IARDTEM B steel of the Heppenstall Co.,Pittsburgh, Pa., may be usable only at a temperature of from 600 to800F, while the metal piece must be at 1,750F. In general, the initialdie temperature will be from 400 to 800F in the forging of titaniumalloys. With economics dictating that there be a difference between thetemperature of the metal piece to be forged and the forging dies, thepractice had arisen of insulating the metal piece from the dies by theuse of interposed asbestos roll board, this to prevent the dies actingas heat sinks for the heat in the hotter metal piece to be forged. Thisis described in the above section entitled BACKGROUND OF THE INVENTION.

Glass cloths which may be used according to this invention are wovenyarns or strands of glass filaments. A glass cloth which has been foundto give very good results at a reasonable price has a warp yarn count of42 and a fill yarn count of 32, a cloth thickness of 0,007 inch, a clothweight of 5.8 ounces per square yard, a plain weave, and a tensilestrength, as measured by ASTM method 579-45, characterized by a minimumaverage breaking strength, pounds per inch, of, for the warp, 250 poundsper inch and, for the fill, 200 pounds per inch. Burlington GlassFabrics Company of New York, New York, supplies such a cloth under thestyle designation No. 7628.

For ease of handling and cutting, it is preferred to obtain this clothin the weave-set variety. The term weave-set is used to refer to acoating of, for example, polymer or starch for holding the yarn orstrands in place in a cloth. The weave may be set with, for example,polyvinyl acetate. When weave-set material is cut, the strands do nottend to frayor fall out, this being otherwise the case when no weave-setis-present. Also, weave-set cloth has a stiffness which'makes cuttingeasier. Additionally, it has been found that weave-set cloth lays inplace and conforms better to hot surface contours than doescloth-lacking weave-set. Weave-set material is also easier to locate forshimming. A glass cloth with a weave-set is, however, not a criticalfactor in the broader aspect of the invention; it has been found thatvery satisfactory results can be obtained with glass cloth made solelyof strands of glass filamentsQ Other glass cloth style numbers whichhave been tried and found to give satisfactory results are as follows,these cloths being available from the Burlington Glass Fabric Company orfrom J. P. Stevens and Company of New York, New York: 1,528 having athickness of 0.007 inch and a weight of 5.95 ounces per square yard,1,610 having a thickness of 0.0047 inch and a weight of 3.87 ounces persquare yard, 7,500 having a thickness of 0.0138 inch and a weight of9.55 ounces per square yard, and 1,597 having a thickness of 0.0423 inchand a weight of 37.42 ounces per square yard. These may be provided incoated or uncoated styles.

Work with glass cloth will generally cause an itching sensation when aman first starts working with it, but he becomes quickly, i.e. withinone day to two weeks, acclimated to this, so that it is no longer felt.All available evidence indicates that there is no health hazardassociated with this itching.

We have used what is referred to as E-glass as the particular glasscomposition of the glass cloths. E-glass has a composition as follows:52-65 percent silicon dioxide, 16-25 percent calcium oxide, -l216percent aluminum oxide, 8-13 percent boron oxide, O-l percent sodium-and potassium oxide, and -6 percent magnesium oxide. We have found thatthere is almost no melting of this composition during a forgingoperation according to the present invention. The forging comes out ofthe forging process having impressed on its surface substantially thesame weave pattern visible in the glass cloth. This indicates that thereis substantially no melting of the glass composition occurring. Lookingat the forging removed from the dies, it is possible to still observethe individual strands of thecloth.

Some glass beads are noted at the ends of torn pieces of the cloth, andit is believed that this is an outgrowth of an intermixing, with theE-glass material of the cloth, of the glass frit composition being usedto protect against alpha-case growth.

While it is preferred to use woven glass cloth, glass mats, e.g.,unwoven assemblages of glass filaments, may also be used.

It is known that a certain amount of lubricating effect can be obtainedfrom the glass frit material used in protecting against alpha-casegrowth. Thus, there may be a certain amount of lubrication arising herewhere both glass frit and glass cloth compositions are present. However,it is believed that the glass cloth operates in the present inventionprimarily through its insulative effect. a

Lubricants which may be used in the forging operations are a highload-carrying capacity oil with graphite suspended in it, ahighload-carrying capacity oil containing a fatty material in addition tographite, a high load-carrying capacity oil carrying organic metalcompounds, and other standard forging lubricants. Oils of highload-carrying capacity are characterized'by resistance to decompositionunder forging pressures. Examples of commercial products are WynnAluminum l-A available from the Wynn Oil Company of Azusa, Calif, andHodson Forging Die Lubricant N0. 17 produced by the Hodson Corporationof Chicago, -Ill. These commercial products may be cut with additionalvehicle for the purpose of reducing lubricant residue buildup.

D. Noteworthy Features of the Process The present invention is generallyapplicable in any forging process where there is a difference intemperature between the metal piece to be forged and the forging dies.It has particular application where there is a large difference intemperature, such as is the case in titanium forging, where temperaturedifference between the workpiece and the dies may be typically 600 to1,300F at the start of a forging operation.

In the case of titanium forging, we have found the present inventiontobe particularly successful in the case of the alloys Ti-6Al-4V andTi-6Al-6V-2Sn. The present invention is, however, applicable generallyin the case of titanium alloys and in particular in those cases whereasbestos insulation, such as asbestos roll board, has been used in thepast. Glass cloth of 0.007 inch thickness has been found to beequivalent to asbestos roll board l/l6 inch thickness insofar asinsulation qualities under pressure are concerned, i.e., temperaturefall as a function of time is the same. We have found, however, that incases where a 1/16-inch asbestos roll board material had been used toprovide insulation of the material to be forged from the dies, it ispossible to use glass cloth all the way down to 0.004 inch thickness. Incertain cases, it may even bepossible to go somewhat-below thisthickness. lt ispresently preferred to use a thickness of 0.007 inch. Asmight be expected, it has been found that thicker glass cloths can beused, a glass cloth of 0.04 inch thickness having been actually tried,but the higher cost of the thicker material makes it relativelyunattractive as compared to the 0.007 inch thick glass cloth. When using0.007 inch thick glass cloth material as a one to one substitute for1/l6-inch thick asbestos roll board, it is presently possible toexperience a significant materials-cost sav-' ing. Even if the glasscloth is used in double thicknesses, there is still nevertheless a verysignificant cost saving according to the present invention as compared-to' practice withasbestos insulation. As an example, in

the-present invention it is quite often not necessary to machineforgings before subjecting them to ultrasonic inspection. In addition,the surface appearance of forgings made according to the presentinvention is also aesthetically much more pleasing to the eye than isthe surface appearance of forgings produced according to I the priorpractice using asbestos insulation.

It was unexpected that the use of glass cloth as in the presentinvention would yield a workpiece surface of much more pleasingappearance as compared to that remaining after the use of asbestos.Additionally, it was unexpected thatit would quite often no longer benecessary to machine the surface'smooth before carrying out ultrasonictesting.

As. an additional advantage of glass cloth, it has been Example I Withreference to FIG. 3, the titanium alloy cylinder 20 of alloy-typeTi-6Al-4V, having cylinder dimen sions 2 inches in height and 2 /2inches in diameter and preheated to a temperature of 1,750F, has beenplaced on a lower die-steel platen 2l-which-is maintained at atemperature of 750F by heating coils (not shown) in the platen.interposed between the bottom of the cylinder and the lower platen is asheet 22 of insulating substance, e.g., glass'cloth. Onto the top'of thecylinder there is to be placed likewise a sheet of insulating substanceand above that another platen also held at 750F. The l,750F temperatureto which the cylinder has been preheated is a typical forgingtemperature for the alloyof which it is formed.

FIG. 4 shows the cylinder after it has been compressed under a load of30,000 psi. The type of metal deformation shown is that which one wouldobtain by using insulating sheets of l/l6-inch thick asbestos rollboard, a'pliable sheet material of asbestos fibers with a clay binder.FIG. 5 illustrates the type of metal deformation that one would obtainby compressing the cylinder using no insulative sheet. According to thepresent invention, it has been discovered that, as compared withl/l6-inch asbestos roll board, roughly the. same reduction in heightfrom 2 inches to 0.8-0.9 inch, and the same pancaked workpieceappearance, is possible when using glass cloth 22 having, for example, athickness of 0.007 inch. Examination of the upper and lower faces of thecompressed cylinders has shown die chill 5 which suggest reduced metalflow, actually yielded the flattened pancake configuration of FIG. 4which shows significantly more metal flow.

Example 11 A forging of titanium alloy Ti-6Al-4V is produced 8 accordingto FIGS. 1 and 2. The breadth of the forging at the left end in FIG. 2is-8 inches, while the breadth at the right end has increased to 10inches. The length of the forging, left and right in FIG. 2, is 10 feet.Rib 18 attained a thickness of 2 /2 inches; its height as measuredupwards from the plane of web 19, was 1 /2 inches. The thickness of theweb was -1 inch. Glass cloths l4 and 16 were provided as style No. 7628.This cloth, which has a thickness of 0.007 inch and a breadth of 38inches, was cut to the proper length and then folded down the middle togive material of 19- inches width and double thickness, i.e., 0.014 inchthick. The initial temperature of the metal piece 15 was l,750F, whilethe initial die temperature was 800F. The forged piece was left withimpressions 24 of the glass cloth on its surface and this pattern wasmuch more pleasing to the eye than the pockmarked surface obtained whenusing asbestos roll board.

It will be understood that the above description of th presentinvention. is susceptible to various modifications, changes, andadaptations and the same are intended to be comprehended within the'meaning and range of equivalents of the appended claims.

What is claimed is: I

1. A method of forging a metal piece between dies, comprising the stepsof heating the metal pieceto a temperature above that of the dies,insulating the higher temperature metal piece from the dies with glasscloth, squeezing the insulated metal piece between the dies for causingmetal flow for forging, and during said squeezing and forging step,maintaining said cloth in its original filamentary condition so'thatfollowing squeezing and forging the individual filaments of the glasscloth are still visible.

2. A method as claimed in piece is titanium.

3. A method as claimed in claim I, wherein the metal piece is a titaniumalloy of the alpha-type and the temperature to which the metal piece isheated is from 1,500 to 2,000F.

4. A method as. claimed in claim 3, have a temperature of 400 to 800F.

5. A method as claimed in claim 1, wherein the metal piece is analpha-beta titanium alloy and the metal temperature to which the metalpiece is heated is l,400 to I,800F.

6. A method as claimed in claim 5, wherein the dies have a temperatureof 400 to 800F.

7. A method as claimed in claim 1, wherein the metal piece is analpha-beta titanium alloy and the step of squeezing is carried outwithin a temperature range which includes the beta transus and extendsto 300F above the beta transus.

8. A method as'claimed in claim 7, wherein the dies have a temperatureof 400 to 800F.

9. A method as claimed in claim 1, wherein the metal claim 1, whereinthe metal wherein the dies piece is a beta titanium alloy and thetemperature to which the metal l,850F.

10. A method as claimed in claim 9, wherein the dies have a temperatureof 400 to 800F.

11. A method as claimed in claim I, wherein the metal piece is heated toa temperature of 600 to l,400F above the temperature of the dies.

12. A method as claimed in claim 1, wherein the glass cloth exhibits apattern and the pattern is impressed piece is heated is from 1,325 to3,863,325 9 10 5 onto the surface of the metal piece in the step of ofsqueezing includes shimming the metal piece with at Squeezing least oneadditional thickness of glass cloth.

13. A method as claimed in claim 1; wherein the glass cloth has athickness of 00044104 inch 16. method as claimed mclanm 1, wherein theglass 14' A method as chimed in claim 1, wherein Said 5 cloth ISprovided .with lubricant before the step of glass cloth is in theweave-set condition. squeezing- IS. A method as claimed in claim 1,wherein the step Patent No. 3,863,325

Inventor s) Dated February 4, 1975 Thomas B. Gurganus et a1 It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

Col. 5, line 55 [SEAL] A ttes I:

RUTH C. MASON Arresting Officer Change "slulgging" to --slugging--.

' Change "perform" to --preform--.

Change "0,007" to -0.007--.

Change "5 2-6570" to -52-'56Z,--.

Signed and Scaled this seventh D3) Of October 1975 I C. MARSHALL DANN(vmmissiuner ofPalenrs and Trademarks Dedication 3,863,825.Th0mas B.Gurganus, Avon, and Leland L. Gmbb, Parma, Ohio. GLASS CLOTH IN METALFORGING. Patent dated Feb. 4, 1975. Dedication filed March 10, 1975, bythe assignee, Aluminum Oompcmy of America. Hereby dedicates to thePublic the remaining term of said patent.

[Oyfioz'al Gazette June 2%, 1.975.]

1. A method of forging a metal piece between dies, comprising the stepsof heating the metal piece to a temperature above that of the dies,insulating the higher temperature metal piece from the dies with glasscloth, squeezing the insulated metal piece between the dies for causingmetal flow for forging, and during said squeezing and forging step,maintaining said cloth in its original filamentary condition so thatfollowing squeezing and forging the individual filaments of the glasscloth are still visible.
 2. A method as claimed in claim 1, wherein themetal piece is titanium.
 3. A method as claimed in claim 1, wherein themetal piece is a titanium alloy of the alpha-type and the temperature towhich the metal piece is heated is from 1,500* to 2,000*F.
 4. A methodas claimed in claim 3, wherein the dies have a temperature of 400* to800*F.
 5. A method as claimed in claim 1, wherein the metal piece is analpha-beta titanium alloy and the metal temperature to which the metalpiece is heated is 1,400* to 1,800*F.
 6. A method as claimed in claim 5,wherein the dies have a temperature of 400* to 800*F.
 7. A method asclaimed in claim 1, wherein the metal piece is an alpha-beta titaniumalloy and the step of squeezing is carried out within a temperaturerange which includes the beta transus and extends to 300*F above thebeta transus.
 8. A method as claimed in claim 7, wherein the dies have atemperature of 400* to 800*F.
 9. A method as claimed in claim 1, whereinthe Metal piece is a beta titanium alloy and the temperature to whichthe metal piece is heated is from 1,325* to 1,850*F.
 10. A method asclaimed in claim 9, wherein the dies have a temperature of 400* to800*F.
 11. A method as claimed in claim 1, wherein the metal piece isheated to a temperature of 600* to 1,400*F above the temperature of thedies.
 12. A method as claimed in claim 1, wherein the glass clothexhibits a pattern and the pattern is impressed onto the surface of themetal piece in the step of squeezing.
 13. A method as claimed in claim1, wherein the glass cloth has a thickness of 0.004-0.04 inch.
 14. Amethod as claimed in claim 1, wherein said glass cloth is in theweave-set condition.
 15. A method as claimed in claim 1, wherein thestep of squeezing includes shimming the metal piece with at least oneadditional thickness of glass cloth.
 16. A method as claimed in claim 1,wherein the glass cloth is provided with lubricant before the step ofsqueezing.